File: /usr/src/linux/fs/hpfs/file.c
1 /*
2 * linux/fs/hpfs/file.c
3 *
4 * Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
5 *
6 * file VFS functions
7 */
8
9 #include <linux/string.h>
10 #include <linux/sched.h>
11 #include <linux/smp_lock.h>
12 #include "hpfs_fn.h"
13
14 #define BLOCKS(size) (((size) + 511) >> 9)
15
16 /* HUH? */
17 int hpfs_open(struct inode *i, struct file *f)
18 {
19 lock_kernel();
20 hpfs_lock_inode(i);
21 hpfs_unlock_inode(i); /* make sure nobody is deleting the file */
22 unlock_kernel();
23 if (!i->i_nlink) return -ENOENT;
24 return 0;
25 }
26
27 int hpfs_file_release(struct inode *inode, struct file *file)
28 {
29 lock_kernel();
30 hpfs_write_if_changed(inode);
31 unlock_kernel();
32 return 0;
33 }
34
35 int hpfs_file_fsync(struct file *file, struct dentry *dentry, int datasync)
36 {
37 /*return file_fsync(file, dentry);*/
38 return 0; /* Don't fsync :-) */
39 }
40
41 /*
42 * generic_file_read often calls bmap with non-existing sector,
43 * so we must ignore such errors.
44 */
45
46 secno hpfs_bmap(struct inode *inode, unsigned file_secno)
47 {
48 unsigned n, disk_secno;
49 struct fnode *fnode;
50 struct buffer_head *bh;
51 if (BLOCKS(inode->u.hpfs_i.mmu_private) <= file_secno) return 0;
52 n = file_secno - inode->i_hpfs_file_sec;
53 if (n < inode->i_hpfs_n_secs) return inode->i_hpfs_disk_sec + n;
54 if (!(fnode = hpfs_map_fnode(inode->i_sb, inode->i_ino, &bh))) return 0;
55 disk_secno = hpfs_bplus_lookup(inode->i_sb, inode, &fnode->btree, file_secno, bh);
56 if (disk_secno == -1) return 0;
57 if (hpfs_chk_sectors(inode->i_sb, disk_secno, 1, "bmap")) return 0;
58 return disk_secno;
59 }
60
61 void hpfs_truncate(struct inode *i)
62 {
63 if (IS_IMMUTABLE(i)) return /*-EPERM*/;
64 i->i_hpfs_n_secs = 0;
65 i->i_blocks = 1 + ((i->i_size + 511) >> 9);
66 i->u.hpfs_i.mmu_private = i->i_size;
67 hpfs_truncate_btree(i->i_sb, i->i_ino, 1, ((i->i_size + 511) >> 9));
68 hpfs_write_inode(i);
69 }
70
71 int hpfs_get_block(struct inode *inode, long iblock, struct buffer_head *bh_result, int create)
72 {
73 secno s;
74 s = hpfs_bmap(inode, iblock);
75 if (s) {
76 bh_result->b_dev = inode->i_dev;
77 bh_result->b_blocknr = s;
78 bh_result->b_state |= (1UL << BH_Mapped);
79 return 0;
80 }
81 if (!create) return 0;
82 if (iblock<<9 != inode->u.hpfs_i.mmu_private) {
83 BUG();
84 return -EIO;
85 }
86 if ((s = hpfs_add_sector_to_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1)) == -1) {
87 hpfs_truncate_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1);
88 return -ENOSPC;
89 }
90 inode->i_blocks++;
91 inode->u.hpfs_i.mmu_private += 512;
92 bh_result->b_dev = inode->i_dev;
93 bh_result->b_blocknr = s;
94 bh_result->b_state |= (1UL << BH_Mapped) | (1UL << BH_New);
95 return 0;
96 }
97
98 static int hpfs_writepage(struct page *page)
99 {
100 return block_write_full_page(page,hpfs_get_block);
101 }
102 static int hpfs_readpage(struct file *file, struct page *page)
103 {
104 return block_read_full_page(page,hpfs_get_block);
105 }
106 static int hpfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
107 {
108 return cont_prepare_write(page,from,to,hpfs_get_block,
109 &page->mapping->host->u.hpfs_i.mmu_private);
110 }
111 static int _hpfs_bmap(struct address_space *mapping, long block)
112 {
113 return generic_block_bmap(mapping,block,hpfs_get_block);
114 }
115 struct address_space_operations hpfs_aops = {
116 readpage: hpfs_readpage,
117 writepage: hpfs_writepage,
118 sync_page: block_sync_page,
119 prepare_write: hpfs_prepare_write,
120 commit_write: generic_commit_write,
121 bmap: _hpfs_bmap
122 };
123
124 ssize_t hpfs_file_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
125 {
126 ssize_t retval;
127
128 retval = generic_file_write(file, buf, count, ppos);
129 if (retval > 0) {
130 struct inode *inode = file->f_dentry->d_inode;
131 inode->i_mtime = CURRENT_TIME;
132 inode->i_hpfs_dirty = 1;
133 }
134 return retval;
135 }
136
137